Progress in Informatics, No. 1, pp. 75-81, (2005) 75 Received December 1, 2004; Accepted December 2, 2004. 1 Introduction Recently there have been many studies regarding all-optical network technology. In future all-optical networks, it is assumed that wavelength paths will be dynamically reconfigured in cases of network protection/restoration and path switching driven by ser- vice applications. Accordingly, we must consider a number of new issues that have not been addressed in terms of traditional networks. SuperSINET, which began in January 2002 as an optical transport infrastructure for high-end scientific research, has been operating at 10 Gbps transmission speed by deploying wavelength division multiplexing (WDM) and optical cross-connect (OXC, or some- times referred as photonic cross-connect PXC) to maintain quality and reliability of transmission. How- ever, operation of the transport system is based on stat- ic control; the development of more economical and enhanced control systems based on recent technologies thus poses a challenge in the realization of a next- generation SuperSINET. When the wavelength path in an all-optical network is dynamically reconfigured, the accumulated physical layer parameters such as chromatic dispersion (CD) along the path are changed. Even if a slope-compen- sating dispersion compensation fiber (SC-DCF) is applied for each fiber span, residual chromatic dispersion remains, due to limitations in production accuracy in terms of the length of the SC-DCF. Moreover, CD characteristics vary according to environmental condi- tions such as ambient temperature [3]. Hence, it is considered that the residual CD value along the entire path changes from one path to another and that this value changes with time. Therefore, it is possible that signal quality will be degraded without proper compensation in the residual CD for data rates over 40 Gbps. Several studies examining CD along the entire Field trial of all-optical 40 Gbps transmission system for next-generation networks Mikio Yagi 1 , Shinya Tanaka 2 , Shuichi Satomi 3 , Shiro Ryu 4 , Ahmad Suffian Mohamad 5 , Susumu Yoneda 6 , Takayuki Fujino 7 , Shoichiro Asano 8 1, 2, 3, 4, 6 Information and Communication Laboratories, R&D Division, Japan Telecom Co., Ltd 5 University of Tokyo 6, 7, 8 National Institute of Informatics ABSTRACT The National Institute of Informatics (NII) has been conducting joint research with Japan- Telecom to develop a 40 Gbps optical transport system for the next-generation SuperSINET. We report on the recent results of field trials focused on automatic chromatic dispersion compensation and path protection/restoration applied to the future SuperSINET as key technologies required to maintain the quality of transmission, to reduce operational costs, and to facilitate the enhancement of network capabilities. From the results of the field trial, we have confirmed that an automatic optical path control system is essential in an all-optical wavelength path network. KEYWORDS Optical communication, chromatic dispersion compensation, protection/restoration, GMPLS, multi-layer integration. Research Paper